﻿// LexicalHandler.java - optional handler for lexical parse events.
// http://www.saxproject.org
// Public Domain: no warranty.
// $Id$
using System;

namespace org.xml.sax.ext
{

    /**
     * SAX2 extension handler for lexical events.
     *
     * <blockquote>
     * <em>This module, both source code and documentation, is in the
     * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
     * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
     * for further information.
     * </blockquote>
     *
     * <p>This is an optional extension handler for SAX2 to provide
     * lexical information about an XML document, such as comments
     * and CDATA section boundaries.
     * XML readers are not required to recognize this handler, and it
     * is not part of core-only SAX2 distributions.</p>
     *
     * <p>The events in the lexical handler apply to the entire document,
     * not just to the document element, and all lexical handler events
     * must appear between the content handler's startDocument and
     * endDocument events.</p>
     *
     * <p>To set the LexicalHandler for an XML reader, use the
     * {@link org.xml.sax.XMLReader#setProperty setProperty} method
     * with the property name
     * <code>http://xml.org/sax/properties/lexical-handler</code>
     * and an object implementing this interface (or null) as the value.
     * If the reader does not report lexical events, it will throw a
     * {@link org.xml.sax.SAXNotRecognizedException SAXNotRecognizedException}
     * when you attempt to register the handler.</p>
     *
     * @since SAX 2.0 (extensions 1.0)
     * @author David Megginson
     * @version 2.0.1 (sax2r2)
     */
    public interface LexicalHandler
    {

        /**
         * Report the start of DTD declarations, if any.
         *
         * <p>This method is intended to report the beginning of the
         * DOCTYPE declaration; if the document has no DOCTYPE declaration,
         * this method will not be invoked.</p>
         *
         * <p>All declarations reported through 
         * {@link org.xml.sax.DTDHandler DTDHandler} or
         * {@link org.xml.sax.ext.DeclHandler DeclHandler} events must appear
         * between the startDTD and {@link #endDTD endDTD} events.
         * Declarations are assumed to belong to the internal DTD subset
         * unless they appear between {@link #startEntity startEntity}
         * and {@link #endEntity endEntity} events.  Comments and
         * processing instructions from the DTD should also be reported
         * between the startDTD and endDTD events, in their original 
         * order of (logical) occurrence; they are not required to
         * appear in their correct locations relative to DTDHandler
         * or DeclHandler events, however.</p>
         *
         * <p>Note that the start/endDTD events will appear within
         * the start/endDocument events from ContentHandler and
         * before the first 
         * {@link org.xml.sax.ContentHandler#startElement startElement}
         * event.</p>
         *
         * @param name The document type name.
         * @param publicId The declared public identifier for the
         *        external DTD subset, or null if none was declared.
         * @param systemId The declared system identifier for the
         *        external DTD subset, or null if none was declared.
         *        (Note that this is not resolved against the document
         *        base URI.)
         * @exception SAXException The application may raise an
         *            exception.
         * @see #endDTD
         * @see #startEntity
         */
        void startDTD(String name, String publicId,
                       String systemId);//	throws SAXException;


        /**
         * Report the end of DTD declarations.
         *
         * <p>This method is intended to report the end of the
         * DOCTYPE declaration; if the document has no DOCTYPE declaration,
         * this method will not be invoked.</p>
         *
         * @exception SAXException The application may raise an exception.
         * @see #startDTD
         */
        void endDTD();//	throws SAXException;


        /**
         * Report the beginning of some internal and external XML entities.
         *
         * <p>The reporting of parameter entities (including
         * the external DTD subset) is optional, and SAX2 drivers that
         * report LexicalHandler events may not implement it; you can use the
         * <code>http://xml.org/sax/features/lexical-handler/parameter-entities</code>
         * feature to query or control the reporting of parameter entities.</p>
         *
         * <p>General entities are reported with their regular names,
         * parameter entities have '%' prepended to their names, and 
         * the external DTD subset has the pseudo-entity name "[dtd]".</p>
         *
         * <p>When a SAX2 driver is providing these events, all other 
         * events must be properly nested within start/end entity 
         * events.  There is no additional requirement that events from 
         * {@link org.xml.sax.ext.DeclHandler DeclHandler} or
         * {@link org.xml.sax.DTDHandler DTDHandler} be properly ordered.</p>
         *
         * <p>Note that skipped entities will be reported through the
         * {@link org.xml.sax.ContentHandler#skippedEntity skippedEntity}
         * event, which is part of the ContentHandler interface.</p>
         *
         * <p>Because of the streaming event model that SAX uses, some
         * entity boundaries cannot be reported under any 
         * circumstances:</p>
         *
         * <ul>
         * <li>general entities within attribute values</li>
         * <li>parameter entities within declarations</li>
         * </ul>
         *
         * <p>These will be silently expanded, with no indication of where
         * the original entity boundaries were.</p>
         *
         * <p>Note also that the boundaries of character references (which
         * are not really entities anyway) are not reported.</p>
         *
         * <p>All start/endEntity events must be properly nested.
         *
         * @param name The name of the entity.  If it is a parameter
         *        entity, the name will begin with '%', and if it is the
         *        external DTD subset, it will be "[dtd]".
         * @exception SAXException The application may raise an exception.
         * @see #endEntity
         * @see org.xml.sax.ext.DeclHandler#internalEntityDecl
         * @see org.xml.sax.ext.DeclHandler#externalEntityDecl 
         */
        void startEntity(String name);//	throws SAXException;


        /**
         * Report the end of an entity.
         *
         * @param name The name of the entity that is ending.
         * @exception SAXException The application may raise an exception.
         * @see #startEntity
         */
        void endEntity(String name);//	throws SAXException;


        /**
         * Report the start of a CDATA section.
         *
         * <p>The contents of the CDATA section will be reported through
         * the regular {@link org.xml.sax.ContentHandler#characters
         * characters} event; this event is intended only to report
         * the boundary.</p>
         *
         * @exception SAXException The application may raise an exception.
         * @see #endCDATA
         */
        void startCDATA();//	throws SAXException;


        /**
         * Report the end of a CDATA section.
         *
         * @exception SAXException The application may raise an exception.
         * @see #startCDATA
         */
        void endCDATA();//	throws SAXException;


        /**
         * Report an XML comment anywhere in the document.
         *
         * <p>This callback will be used for comments inside or outside the
         * document element, including comments in the external DTD
         * subset (if read).  Comments in the DTD must be properly
         * nested inside start/endDTD and start/endEntity events (if
         * used).</p>
         *
         * @param ch An array holding the characters in the comment.
         * @param start The starting position in the array.
         * @param length The number of characters to use from the array.
         * @exception SAXException The application may raise an exception.
         */
        void comment(char[] ch, int start, int length);//	throws SAXException;

    }

    // end of LexicalHandler.java
}